Before you can choose a backup solution, you have to know what files you want backed up.

In order to decide what files you want to back up, you have to know what files you’ve got on your system as well as various information about them:

What programs and peripherals are creating the files that you want backed up. Where — as in, where on your computer’s storage, or possibly, where on a network storage device — are these files are created and saved to.

It’s possible that the backup utility you use will a.) ask you the right questions, and b.) find the directories and files that you care about. But if you don’t know the answers, you can’t tell the utility what to do and you can’t be sure it’s doing what you need.

What programs and peripherals create files?

It’s easy to lose track of what creates/saves files to the computer.

Every time you use an office productivity application, such as Microsoft Word/Excel/PowerPoint, or OpenOffice, you’re creating, and presumably saving, files.

Also, other devices that connect/sync to your computer may create/transfer files. For example, your smartphone, tablet, digital camera, or MP3 player may create files that can be backed up.

Where are the files?

In order to tell a backup service to backup your files, you have to know not only which ones you want — e.g., documents, music and photos you create, but not documents you’ve downloaded — but also where on your computer they are.

On Windows PCs:

“Windows 7 uses libraries,” according to Ed Bott, author and a blogger for ZDnet on Windows and other technology issues. “By default, Documents are stored in the Documents folder within your user profile. You can add a separate location to a library (and optionally make it the default save location for that datatype), or you can change the default local Documents folder to be a location of your choosing.”

On MacOS:

For MacOS users, places in your directory structure that are likely (keeping in mind that I’m not a Mac user, this comes from consulting a MacOS-using friend plus some searching) to have files you may want to back up include:

o Your “home” folder, which is /Users/[yourname] — often abbreviated as “~”, e.g. /Users/grumpy/helloworld can be done as ~/helloworld

o Bookmarks and other configuration data (as opposed to actual content) created/used by programs, like iCal calendars, Mail accounts and rules, Address Book contents. These are mostly in ~/Library, e.g.

~/Library/Safari/Bookmarks.plist

~/Library/Keychains/

~/Library/Application Support/AddressBook

~/Library/Calendars

o Shared Folders and Public Folder — if you’ve put anything here you want to save.

As somebody still using Windows XP on my primary machine (my new notebook is Windows 7, though), I’m still accustomed to Windows saving to My Documents by default, which in turn by default is part of the top Explorer view of “Desktop” or “My Computer.” My desktop machine has multiple hard drives, and I try to use the C: drive for software, and the D: and E: drives for data — currently, about 250GB of data, including multimedia (photos, video, music).

Even so, my C:/Documents and Settings folder has (after close to four years of using the computer) slightly over 50GB — 50,000+ files in it. Of this, about 14GB are in the Application Data subdirectory, 30GB in My Documents, and 5GB in Local Settings. (For comparison, there’s only about 30GB of software on my C: drive.)

And you may have files to backup from multiple external hard drives, NAS devices and removable media.

Once you’ve determined what files you have, and where they’re located, you’re ready for the next steps in deciding on a backup strategy and selecting a backup solution.